Ligand dose-dependent activation of signaling pathways through the gustatory receptor NlGr11 linked to feeding efficacy in Nilaparvata lugens.

Insects often face both conditions with sufficient nutrients and undernutrition in the field. Through gustatory receptors, insects sense nutrients and regulate their physiological functions such as feeding and reproduction. However, it is still unclear whether signaling pathways activated by gustatory receptors depend on the concentration of nutrients and whether the difference in signaling pathways directly affects insects' physiological functions. Herein, we found that a sugar gustatory receptor, NlGr11, from the brown planthopper (BPH), Nilaparvata lugens, activated G protein-coupled signaling and ionotropic pathways when bound to high galactose concentration. BPHs subsequently demonstrated longer feeding time, more feeding amount, and higher vitellogenin (NlVg) expression than those bound to low galactose concentrations, which only activated the ionotropic pathway. For the first time, our findings linked plant nutrient conditions, signaling pathways activated by nutrients and their gustatory receptors, and nutrient dose-dependent feeding efficacy and Vg expression in an insect. This will help us to better understand the molecular mechanism on feeding strategies of insects in plant stages with different nutritional conditions. This article is protected by copyright. All rights reserved.